Official Rookie Mistake Discussion

Official discussion thread for Rookie Mistake. Please do not post any spoilers or big hints.

Comments

  • edited November 2020

    God that last trap got me killing myself inside LOL
    That being said, am I getting senile or should this work in Sage?

    sage: discrete_log(Mod(23, 7 * 13), Mod(4, 7 * 13), ord=6 * 12)
    ValueError: No discrete log of 23 found to base 4
    

    whereas the answer should be 5? If you change ord to 6 (its real order) the same occurs.

    Had to whip out my own implementation to get this to work.

    Hack The Box

  • edited November 2020

    Nice challenge @willwam845!

    @ngoctnq This is indeed weird in my opinion. It does work for ord = 6, or without specifying an order in my case

    sage: discrete_log(Mod(23, 7 * 13), Mod(4, 7 * 13), ord=6)
    5
    sage: discrete_log(Mod(23, 7 * 13), Mod(4, 7 * 13))
    5
    

    But as the doc states: ord - integer (multiple of order of base, or None), any multiple should work... but it doesn't...

    ArtemisFY
    OSCP

  • edited November 2020

    @ArtemisFY Hey, thanks for the help with the other chall :blush: BTW, which version of Sage are you cranking? I tried both 9.1 and 9.2 through conda and both are bad. Guess I’ll file a bug report or something.

    Edit: Weird. ord=6 (and consequently the code to solve this problem) works now on my machine. Can't trust anything these days.

    Hack The Box

  • So googling around, I got a way to reverse the second part of the flag but for the first part I'm at a bit of a loss. Is it similar to the second half decryption?

    If what I said helped you you can always send some respects ^^

  • I really don't understand how to solve the first one since some important values are not co prime :/

  • edited November 2020

    @underc0very0 For the first part, I don't know if this is hinting too much but it's likely that the non-coprime part doesn't wrap around the modulus. And even if it does, there's an algorithm for it ;)

    Hope this hint helps Fukurou too.

    Hack The Box

  • edited November 2020

    I solved the first part very easily but stuck at the second part
    I think for anyone stuck on the first part he can use some learning from cryptohack.org
    i feel really shocked that most of you guys solving the second part before the first
    I googled a lot but found nothing
    hope someone drops a hint for the second part soon

  • edited November 2020

    Nice challenges @willwam845

    Hint for second part: Chinese theories may help you.

  • Nice challenge @willwam845

    The second part is definitely easier than the first. Google is your friend and plenty of hints already. If you are still stuck on the first part, here is my hint: DONT think about RSA, what would you do to unsquare a number?

    If what I said helped you you can always send some respects ^^

  • I had to take a math course to solve this...

    snuggles

  • edited February 21

    Hello everyone!
    I have solved the DH part but I am really stuck on the RSA part. I think I have found what mathematics are required but I don't know how to use them to solve the problem...
    Any nudge in pm would be appreciated!

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